Polymer treatment for fiberboards



June 23, 1953 M. c. FUQUA POLYMER TREATMENT FoR FIBERBOARDS Filed Aug.ie, 195o 2 Sheets-Sheet Il.`

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b5 Clbboraec June 23, 1953 M. c. FUQUA POLYMER TREATMENT FOR FIBERBOARDSFiled Aug. 16, 1950 2 Sheets-Sheet 2 'lll w u@ N. l. H Tm! .m m e rW.m.r32 M l-l .mdj W um om* o2 O2 o: 02 o@ o@ or o@ om 3 om 0N. 2 OQ Qu/ w//J n. w I/ N F mf O a HH. v f /f E G, V, s /1/ Y o l uca o o a u@ f//^N`4 N; A l A m .uhmm uzoaa zulu xounv. .N N Q D m-mNN.muuanvuu.uzzrnz-Q -J zm1& .U G* M .uomNNsl E l. mmm f mdnkuamk mdDU a* TMEC. mdjw zO mm3# md3k dmm|r uo human-M MIP Patented June 23, 1953POLYMER TREATMENT FOR FIBERBOARS Mack C. Fuqua, Baton Rouge, La.,assgnor to Standard Oil Development Company, a corporation of DelawareApplication August 16, 1950, Serial No. 179,831

f i Claims. 1 i

This invention is for an improved treatment for laminated boards andpaper, using a polymeric material in conjunction with a specic polymercuring treatment, and specifically using sulfur.`

.it has been known that by certain more or less well-known treatments ofmixed hydrocarbon streams containing olens, dioleiins, naphthenes,aromatics, and parafns, there can be produced a polymer having desirabledrying oil properties. One such operation which will produce usefulpolymers from mixed hydrocarbon streams is a clay treating unit. Forinstance, various types of clay treating operations are normallyemployed in order to make hydrocarbons more suitable for motor fuels,such as gasolines. A, steam-cracked hydrocarbon fraction is passed asfeed over the clay at a temperature of 200- 500c F., and in a semi-vaporor liquid state. The gasoline or naphtha fraction is stripped from thepolymer product. The yield of polymer can be varied within limits of 1%to 10% of the feed, depending on the type of feed, temperature, and timeof treatment and certain other Variables in the treating operation.YTemperatures should be as low as possible inA order to preventdegradation of the polymer.

The polymer so produced has valuable uses as a drying oil typeofrmaterial and can be employed as core oil, in paint manufacture,printing inks, andas a wood treating agent, and for similar uses Whereits drying oil properties can be advantageously'utilized. A typicalpolymer oi the type preferred fortbis invention has the followinganalyseszl Y Gravity, API 3 5-10.5 Flash, Cleveland open cup F 2l0Non-Volatile matter, wt. 85 Viscosity, SSU@210 F., sec 1D0-300 lodinenumber 25o-325 It has been found, for instance, that this poly- Vmerfraction is useful as an impregnating agent for laminated boards andpapers, and especially for wood ber boards to be used as outsidecoverings for buildings. A number of serious problems arose, however, inthe actual preparation of the nished boards and similar treatedproducts.

First of all, it was found that an excessive amount of overheating andcharring took place during the oven-curing treatment of thepolymerimpregnated boards. Secondly, there frequently occurred seriousfire hazards from spontaneous combustion o f the boards during lstorage.after uncured sulfur-polymer mixture and shows essencuring. This hazardwill occur with boards impregnated with any type of unsaturated oil orpolymer with unfilled double bonds.

It was discovered that both diiiiculties can be substantially eliminatedby treating the polymer with small amounts of elemental sulfur o1' asuliur-containing compound which is capable of reducing, but notdestroying, the unsaturation of the polymer.

However, satisfactory results are not obtained unless a specific andcritical method is followed in the treatment. Thus, it is necessary totreat the polymer with the sulfur, subject the sulfurized polymer to aninitial precuring at about 300 F. for thirty minutes. Heatingtemperatures of -350 F. and times of from 0.5 to 4 hours arecontemplated. The precise conditions are more or less dependent on thesize of the boards and the amount of polymer and sulfur used. The amountof sulfur used must be sufficient to materially reduce the olei'lnicunsaturation of the polymer, but not enough to give a polymeric materialof excessive viscosity. A concentration of sulfur of from 0.5% to 20%has been found to be adequate. Optimum results are obtained with about5% sulfur.

The board is then treated with the partially cured, sulfurzed polymer,the treating being followed by a heat curing of the board itself.

Figure 1 clearly shows the effect of the addition of sulfur on thetemperature of the polymerimpregnated boards in the curing oven. Curve Aof Figure 1 illustrates the temperature effects shown by oven-treating aboard treated with polymer, but Vusing 'no sulfur. 'At an oventemperature of 225 F., the treated board reached 475 F. with evidencesof marked charring. Curve B shows the eiect of treating the board withan tially the same conditions of overheating and charring as occur inthe boards treated with the polymer alone. g complete absence oftemperature rise on curing oi the board when the sulfur-polymer mixtureis cooked for about four hours before impregnating the board, followedby further curing after the board is impregnated. It has been found byexperimentation that one hour curing time is adequate for the initialheating of the sulfur-polymer mixture. Thus, a very satisfactory methodhas been developed for overcoming the first-outlined difficulty ofoverheating and charring of the boards in the oven. v

In order to study the efficiency of the method as to solving the problemof spontaneous com- Curve C, however, shows the I bustion of the boardsafterA heat treating and during storage, an empirical test was designed.A small section of fiber board (2" x 6" X 1/2") was immersed in thepolymer for about ve seconds, removed, and afterward cured at thedesignated conditions. The thus cured strip was cooled to roomtemperature, in an inert atmosphere, and then-placed in an oxygen-lled'closed Dewar flask. The temperature was measured and recorded atintervals with thermocouple wires imbedded in the ber board. A maximumwas obtained in about ve hours,at .which time spontaneous oxidationoccurs. Roughly, the temperature rise of an isolated board isproportional to the cure time when-using gthe sulfurtreated polymer. I

In Figure 2, the temperature rise 4of Itheiber board samples has beenplotted against the oven cure time in minutes. when the board isadequately cured, there is no tendency toward spontaneous combustion.Thus, at a cure temperature of 225 about 150mmutes would be required togive :adequate curing, while at 325 F., about 12.0'minutes `wouldbarequired. In these tests, about 5% sulfur was employed with thepolymer. Y

It has additionally been discovered that the use of an anti-oxidant as,for instance, those of the aromatic amine or bis-phenol type, such asphenyl-beta-naphthylamine, 2,6-ditertiary-butyi- 4-methy1 phenol, or2,2-p-hydroxy phenyl propane, will prevent the spontaneous temperaturerise of the treated boards. Points C and D on Figure 2 illustrate thisgraphically. A small amount of the anti-oxidant was applied to theboards in a dilute solution .of alcohol.

Other known anti-oxidants which can be employed includephenyl-alpha-naphthylamine, dinaphthyl-p-phenylene diamine, p-isopropoxydiphenylamine, aldol-alpha-naphthylamine, heptylated diphenylamine,naphthol salts Vof polyamines, disalicylal-propylene diamine,hexachloronaphthalene, p (p tolyl-sulfonylamido) diphenylamine,aminophenol, various condensation products of aldehydes, such asformaldehyde or ketones such as acetone with diphenylalnine, anilinewith phenyl-beta-naphthylamine, various hydrocarbon waxes,hydroduinone-type materials such as hydroquinone monobenzel ether,polymerized trimethyl dihydroquinoline, hydroquinone, catechol,3,5-diethy1 catechol, beta-naphthol, diamyl dihydroxyphenyl sulfide ordisulfide, alkylated phenols having a total of 2-11 carbon atoms in 1 3alkyl groups such as the dimethyl phenol isomers, 3-methyl-4-tert. butylphenol, tert.amyl phenol, 2 methyl 4,6 ditert. butyl phenol, and thedi-tert.amyl cresols.

As a specic embodiment of the invention, the following example ispresented:

Example The curve shows that A mixture of a vhighly unsaturatedpolymeric material, such as is obtained by the clay treatment of crackedgasoline fractions, was mixed with about 5% by weight of sulfur and themixture heated at 300 F. for 4 hours. A wood iiber board was thenimpregnated with this partially cured polymerized mixture. The treatedboard was then oven cured for about 2 hours at 300 F. No overheating ofthe board nor charring took place during curing of the board. Nospontaneous combustion of the board was observed during storage afterthe curing treatment.

What is claimed is:

1. The method of treating a wood ber board Which consists essentially inapplying a partly cured olefinic polymer oil formed by clay treating acracked hydrocarbon naphtha, and containing vabout 5 weight percentsulfur, to the wood ber board to impregnate the board with partly curedolenic polymer oil, and then treating the impregnated board at about 225F. to 325 F. for about 2 to 21/2 hours to effect complete cure of thepartly cured oleinic polymer oil with which the wood ber boardisimpregnated.

2. The method .of .mpregnating a wood fiber board which .comprisestreating the wood fiber board with an antioxidant selected from theVclass consisting of aromatic amines .and phenols, irnpregnating thewood fiber board treated with the antioxidant by immersing the wood berboard into a partly cured olenic polymer oil formed by clay treating acracked hydrocarbon naphtha, said partly cured olenic polymer oilcontaining about 5 weight percent of sulfur, to impregnate the boardwith the partly cured oil, and then heating the wood fiber boardimpregnated with the Apartly cured oil to a temperature of about 225 F.to 325 F. for about 2 to 21/2 hours to eifect complete cure of thepartly cured polymer oil with which the wood ber board is impregnated.

3. The method as described in claim v2 in which the antioxidant isI2,2-hydroxy phenol propane.

4. The method as described in claim 2 in which the antioxidant isvphenyl-beta-naphthylamine.

MACK C. FUQUA.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,410,699 Martin Mar. 28, 1922 2,052,172 Frolich Aug. 25, 19362,309,692 Chittick et al. Feb. 2, 1943 2,385,319 Eustis et al. Sept. 18,1945 '2,410,079 .Kellgren Oct. 29, 1946 2,416,232 Soday 1 Feb. 18, 19472,459,891 Nelson et al. Jan. 25, 1949 2,468,724 Beynon May 3, 1949

1. THE METHOD OF TREATING A WOOD FIBER BOARD WHICH CONSISTS ESSENTIALLYIN APPLYING A PARTLY CURED OLEFINIC POLYMER OIL FORMED BY CLAY TREATINGA CRACKED HYDROCARBON NAPHTHA, AND CONTAINING ABOUT 5 WEIGHT PERCENTSULFUR, TO THE WOOD FIBER BOARD TO IMPREGNATE THE BOARD WITH PARTLYCURED OLEFINIC POLYMER OIL, AND THEN TREATING THE IMPREGNATED BOARD ATABOUT 225* F. TO 325* F. FOR ABOUT 2 TO 21/2 HOURS TO EFFECT COMPLETECURE OF THE PARTLY CURED OLEFINIC POLYMER OIL WITH WHICH THE WOOD FIBERBOARD IS IMPREGNATED.